IB 6.1.2.8-1B
Page 6
ABB
2.5.2 Trip time - The time is defined by the overcurrent curves (graph). I²t function is selectable. I²t curves are fixed
and do not vary with pickup settings. If the I²t function is out, the trip times are defined as follows: Default is
Maximum with I²t in.
2.5.3 Reset time - Real time is counted up if the current exceeds the function threshold and counted down if the
current drops below the function threshold. Real time is set to zero when the curent drops below the power pickup
point.
2.5.4 Residual ground current - In a three phase, four wire system the ground fault functions can discriminate
between a ground fault and a neutral current.
2.5.5 Ground fault summing - The reset technique used for long-time and short-time function is applied. i.e, real time
is counted up if the current exceeds the function threshold and counted down if the current drops below the function
threshold. The ground function includes arcing ground summation for tripping. This feature allows arcing grounds
occurring sufficiently close together to be summed so that their magnitude will exceed the threshold setting of the
ground element.
2.6
Current Unbalance
2.6.1 Pickup settings - 5% to 50% in increments of 1% and DISABLED. These changes can be made either via the
keypad and LCD or the NIM communications unit. Default is DISABLED. The current unbalance function is only
available for systems with VIM attached.
2.7
Current Sensor Thresholds
2.7.1 Long time - 0.5X to 1.0X of sensor rating in increments of 0.1.
Short time - 2X to 10X of sensor rating in increments of 1.
Instantaneous - 3X to 12X of sensor rating in increments of 1.
Ground - 100 amps to 1200 amps
300 amps to 1200 amps
500 amps to 1200 amps
Depending on sensor rating. See section 2.5.1
2.8
Information Function
2.8.1 The information function consists of an LCD screen, a mechanical target, a light emitting diode (LED) and six
keypad buttons.
2.8.2 The mechanical target provides indication that the unit has caused a circuit breaker opening. Further
information about the function such as the type of trip, LT, ST, INST, GND, I UNB, V UNB, or UV and the fault
current is displayed when any keypad button in depressed after a trip has occurred, or can be found in the records
menu.
DELAY
SETTING
100 - 800A
SENSORS
1600 - 2500A
3000 - 4200A
MAX
5.2 - 9.5 SEC
0.59 - 1.2 SEC 0.35 - 0.50 SEC
INT
2.1 - 4.2 SEC
0.24 - 0.47 SEC 0.20 - 0.32 SEC
MIN
0.68 - 1.3 SEC 0.07 - 0.18 SEC 0.05 - 0.17 SEC
